1. Field of the Invention
This invention is related, in general, to the field of retractile cords/lines formed from plastic materials and to the field of spearguns utilizing a line attached to the spear for recovery of same. It describes a speargun line formed from retractile materials and the method of producing same.
2. Description of Prior Art
Spearguns developed for underwater use in spearfishing have a longstanding history. Typical examples of same (and of harpoon guns, a related field) can be found in U.S. Pat. Nos. 2,301,789; 2,789,465; 2,964,031; 3,102,525; 3,139,692; 3,153,875; and 4,651,454. The applicant is aware of no prior U.S. Patents focusing specifically on the nature and type of line utilized. Instead, the examples cited focus, where they address the issue at all, on the means and manner by which a standard, nonretractile line may be coiled prior to firing and smoothly dispensed upon release of the spear. Only one patent (U.S. Pat. No. 3,102,525) prescribes a mechanical means by which the line may be recovered--a simple hand cranked reel of the type commonly used for fishing purposes. In actual practice, however, this mechanism is seldom used even when incorporated in a speargun. Thus, the most common, and generally the only, way of recovering spear, line and (hopefully) the targeted fish is for the diver to pull same, hand-over-hand, back to him/her after firing. This results in a tangle of line (generally 18 to 20 feet in length) floating by or around the diver. The line must then be laboriously recoiled/repositioned prior to reuse of the speargun. This is not only dangerous to the diver due to the risk of entanglement occasionally posed by the process, it wastes valuable minutes/air from the set amount available to the diver for his/her dive.
In the second field referenced, that of retractile cords, typical examples of the art may be seen in U.S. Pat. Nos. 2,392,842; 2,413,715; and 2,573,439. U.S. Pat. No. 2,392,842, issued to H. J. Doell in 1946, describes a method of making coiled structures from synthetic linear polymeric materials without the use of a mandrel or cylinder by twisting the filament strands of the materials utilized. U.S. Pat. No. 2,413,715, issued to A. R. Kemp, et al, in 1947 describes a means for producing a retractile electrical cord. Utilizing the teaching of this patent, such cords may be produced by twisting a rubber jacketed electrically conductive line as it is wound in the form of a helix on a mandrel, and then subjecting same to a heat treatment. Similarly, U.S. Pat. No. 2,573,439, describes a retractile cord composed of numerous insulated conductors wound around a central strand of thermo plastic material. The basic method for producing such cords as described in this patent utilizes, once again, the steps of winding the component strands tightly on a mandrel and subjecting same to heat to set the materials, particularly the central strand of thermoplastic material, in their helical configuration. However, none of the methods, materials, or retractile lines described above, or anything similar thereto, have hitherto been utilized for the convenience and assistance of divers.